Electric double-layer capacitors (EDLCs) have attracted significant interest as a promising energy storage solution because of their high-power density, exceptional charge/discharge cycle stability, and extended lifespan. Porous carbon is a key component of EDLCs given its outstanding chemical stability, high electrical conductivity, large specific surface area, and cost effectiveness. We fabricated porous carbon from oak wood as a raw material using an environment-friendly steam activation process (physical activation). Pretreatment (stabilization) was conducted using a mild acid (phosphoric acid) to achieve a high specific surface area and maintain structural stability. Oak wood-derived porous carbon (Oak-PC) produced with varying activation times following phosphate stabilization achieved high specific surface area (1050–1990 m2/ g), pore volume (0.44–0.95 cm3/ g), and carbonization yield (36%). Oak-PC retained ~ 90% of its performance at a high current density (10 A/g), demonstrating superior EDLC performance compared to that of commercial porous carbon. These results were attributed to the significant enhancement of the electrical properties of Oak-PCs, achieved by removing char through phosphate stabilization and strengthening bond stability. This study provides foundational data for developing sustainable energy storage technologies and enhancing the efficiency of next-generation energy storage systems by utilizing environmentfriendly biomass materials such as oak wood.

Electrochemical performance of microporous carbons derived from oak wood for electric double-layer capacitor
    Abstract
    1 Introduction
    2 Experiments
        2.1 Materials and preparation of Oak-PC
        2.2 Characterization of Oak-PC
        2.3 Electrochemical measurements
    3 Results and discussion
        3.1 Thermal properties and crystalline structure of oak stabilized with phosphoric acid
        3.2 Textural properties of Oak-PC for different activation times
        3.3 Electrochemical properties of Oak-PC
    4 Conclusion
    Acknowledgements 
    References

• Jin‑Soo Jeong(Material Application Research Institute, Jeonju University, Jeonju 55069, South Korea)
• Hyeon‑Hye Kim(Material Application Research Institute, Jeonju University, Jeonju 55069, South Korea, School of Polymer Science and Engineering, Chonnam National University, Gwangju 61186, South Korea)
• Byung‑Joo Kim(Material Application Research Institute, Jeonju University, Jeonju 55069, South Korea, Department of Materials Science and Chemical Engineering, Jeonju University, Jeonju 55069, South Korea) Corresponding author
• Kay‑Hyeok An(Department of Materials Science and Chemical Engineering, Jeonju University, Jeonju 55069, South Korea)
• Ju‑Hwan Kim(School of Polymer Science and Engineering, Chonnam National University, Gwangju 61186, South Korea, R&D Group 1, Industrialization Division, Korea Carbon Industry Promotion Agency, Jeonju 54853, South Korea)
• Hye‑Min Lee(R&D Group 1, Industrialization Division, Korea Carbon Industry Promotion Agency, Jeonju 54853, South Korea)